added tests for StorageNMap

Signed-off-by: muraca <mmuraca247@gmail.com>

frame/support/src/storage/mod.rs

@@ -1491,7 +1491,7 @@ pub fn storage_prefix(pallet_name: &[u8], storage_name: &[u8]) -> [u8; 32] {
 #[cfg(test)]
 mod test {
 	use super::*;
-	use crate::{assert_ok, hash::Identity, Twox128};
+	use crate::{assert_ok, hash::Identity, pallet_prelude::NMapKey, Twox128};
 	use bounded_vec::BoundedVec;
 	use frame_support::traits::ConstU32;
 	use generator::StorageValue as _;
@@ -1786,19 +1786,37 @@ mod test {
 	#[crate::storage_alias]
 	type FooDoubleMap =
 		StorageDoubleMap<Prefix, Twox128, u32, Twox128, u32, BoundedVec<u32, ConstU32<7>>>;
+	#[crate::storage_alias]
+	type FooTripleMap = StorageNMap<
+		Prefix,
+		(NMapKey<Twox128, u32>, NMapKey<Twox128, u32>, NMapKey<Twox128, u32>),
+		u64,
+	>;
 
 	#[test]
 	fn contains_prefix_works() {
 		TestExternalities::default().execute_with(|| {
-			assert!(FooDoubleMap::iter_prefix_values(0).next().is_none());
-			assert_eq!(FooDoubleMap::contains_prefix(0), false);
+			// Test double maps
+			assert!(FooDoubleMap::iter_prefix_values(1).next().is_none());
+			assert_eq!(FooDoubleMap::contains_prefix(1), false);
 
 			assert_ok!(FooDoubleMap::try_append(1, 1, 4));
 			assert_ok!(FooDoubleMap::try_append(2, 1, 4));
 			assert!(FooDoubleMap::iter_prefix_values(1).next().is_some());
 			assert!(FooDoubleMap::contains_prefix(1));
 			FooDoubleMap::remove(1, 1);
 			assert_eq!(FooDoubleMap::contains_prefix(1), false);
+
+			// Test N Maps
+			assert!(FooTripleMap::iter_prefix_values((1,)).next().is_none());
+			assert_eq!(FooTripleMap::contains_prefix((1,)), false);
+
+			FooTripleMap::insert((1, 1, 1), 4);
+			FooTripleMap::insert((2, 1, 1), 4);
+			assert!(FooTripleMap::iter_prefix_values((1,)).next().is_some());
+			assert!(FooTripleMap::contains_prefix((1,)));
+			FooTripleMap::remove((1, 1, 1));
+			assert_eq!(FooTripleMap::contains_prefix((1,)), false);
 		});
 	}